Improved exercise ventilatory efficiency with nasal compared to oral breathing in cardiac patients.
Level 2 - randomized trial
Randomized crossover physiological trial
PubMed 39165283 · doi:10.3389/fphys.2024.1380562
What was done
The study assessed the acute effects of nasal versus oral breathing on exercise ventilatory efficiency across four groups: heart failure patients (n=15), chronic coronary syndrome patients (n=15), young healthy controls aged 20–40 years (n=15), and older healthy controls aged ≥45 years (n=12). After a 3-minute warm-up, participants completed two 5-minute bouts on a cycle ergometer at 50% peak power in randomized order—once with nasal breathing and once with oral breathing. Spiroergometry parameters were measured and evaluated using Wilcoxon paired-sample tests and linear mixed models adjusted for sex, height, weight, and test order.
What was found
Across all groups, nasal breathing resulted in significantly lower minute ventilation (V̇E), ventilatory equivalent for carbon dioxide (V̇E/V̇CO2), breathing frequency (fR), and end-tidal O2 partial pressure (PETO2), along with significantly higher tidal volume and end-tidal CO2 partial pressure (PETCO2) compared to oral breathing. In the heart failure group, nasal breathing resulted in a median 35% lower V̇E/V̇CO2, 26% lower fR, and 10% higher PETCO2. Exercise oscillatory ventilation present in 6 patients was markedly reduced, and overall abnormal breathing patterns improved in 80% of cardiac patients.
Why it matters
Inefficient exercise ventilation predicts disease progression and mortality in cardiovascular disease. These findings show that nasal breathing can acutely improve ventilatory efficiency and stabilize breathing abnormalities during moderate exertion in cardiac patients.
Limits
The sample size was small (57 total participants, 15 per cardiac group). The trial assessed only brief 5-minute bouts at a single submaximal intensity (50% peak power), leaving high-intensity feasibility, long-term training adherence, and clinical outcomes unaddressed.
Cited by
- partial Nasal breathing increases oxygen delivery deeper into cells because of carbon dioxide restriction.